Observations of Tilting Meddies

Walsh, David; Richardson, Philip L.; Lynch, Jim

doi:10.1175/1520-0485(1996)026<1023:ootm>2.0.co;2

Cited by 9 publications

(7 citation statements)

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“…Shapiro and coworkers (1995) further showed by a self-similarity argument that meddies undergo a substantial adoption process north of the latitude of Gibraltar before these are converted into more stable lenses as found in the Canary Basin. Even there, their rotation axes may be tilted transversely with respect to the meddy translation direction due to external mean geostrophic shear (Walsh et al 1996). Further evidence for a ''stop and go'' behavior of meddies was observed by moored current meters in the central Canary Basin.…”

Section: Acoustic Effects Caused By a Rotating Lensmentioning

confidence: 96%

“…Hence, travel-time differences due to the meddy rotation are considerably larger than those due to the lens drift. According to observational data reported in the literature (Armi and Zenk 1984;Zenk et al 1992;Prater and Sanford 1994;Käse and Zenk 1996;Walsh et al 1996), usually 12 km Յ R Յ 50 km with more typical values being 25-40 km. A meddy's extent in depth is typically 0.6-1.4 km and from surface to about 3 km in extreme cases.…”

Section: Acoustic Effects Caused By a Rotating Lensmentioning

confidence: 96%

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Simulations of Acoustic Imprints of Meddies in the Iberian Basin: Toward Acoustic Detection of Meddies

Mikhin¹,

Godin²,

Boebel³

et al. 1997

J. Atmos. Oceanic Technol.

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Ocean currents' effect on long-range sound propagation, though considerable in many cases, is difficult to separate from much stronger effects due to sound speed inhomogeneities, as flow velocity is usually much smaller than typical variations in the sound speed. Dramatic improvement can be achieved in reciprocal transmission experiments when sound signals propagate in opposite directions between two transceivers (sourcereceiver pairs). The presence of a current results in the breaking of the principle of acoustic reciprocity, thus making it possible to use nonreciprocity of acoustic field as an indicator of water movement. In this paper, reciprocal acoustic transmissions through a submesoscale interthermocline lens of Mediterranean Water (meddy) in the Atlantic are considered theoretically as a possible tool for meddies detection. A simple model of acoustic ray-travel-time nonreciprocity due to a meddy is proposed. The analytic estimates obtained from the model show that the influence of rotary flow is more important than that of drift and seems to be measurable. The problem is studied in more detail via computer simulations. The environmental model used in the simulations corresponds to case studies performed in the Iberian Basin in 1989 and 1991. Numerical simulations show that travel times between two transceivers can be gathered into several groups; for the most part, rays in each set have similar geometry for both propagation directions. However, the lens strongly affects the number of rays in each group, their launch angles, and number of surface interactions, making it impossible to identify these arrivals as required for conventional ocean acoustic tomography. In spite of complexity of ray structure, travel-time nonreciprocity predicted by the model proposed is in good agreement with numerical results. This fact suggests that the model could be used to estimate some parameters of a meddy.

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Section: Acoustic Effects Caused By a Rotating Lensmentioning

confidence: 96%

Section: Acoustic Effects Caused By a Rotating Lensmentioning

confidence: 96%

Simulations of Acoustic Imprints of Meddies in the Iberian Basin: Toward Acoustic Detection of Meddies

Mikhin¹,

Godin²,

Boebel³

et al. 1997

J. Atmos. Oceanic Technol.

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“…Deformation flows always appear near topography boundaries, coherent vortices, jets, large-scale gyres or other non-uniform flows. More generally, an arbitrary external perturbation can be expanded into a Taylor series up to the second-order terms, which gives the following flow form [54,55,[57][58][59]61,84,89,[91][92][93][94][95][96][97][98]…”

Section: External Deformation Flowmentioning

confidence: 99%

Vortex Interactions Subjected to Deformation Flows: A Review

Koshel

Ryzhov

Carton

2019

Fluids

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Deformation flows are the flows incorporating shear, strain and rotational components. These flows are ubiquitous in the geophysical flows, such as the ocean and atmosphere. They appear near almost any salience, such as isolated coherent structures (vortices and jets) and various fixed obstacles (submerged obstacles and continental boundaries). Fluid structures subject to such deformation flows may exhibit drastic changes in motion. In this review paper, we focus on the motion of a small number of coherent vortices embedded in deformation flows. Problems involving isolated one and two vortices are addressed. When considering a single-vortex problem, the main focus is on the evolution of the vortex boundary and its influence on the passive scalar motion. Two vortex problems are addressed with the use of point vortex models, and the resulting stirring patterns of neighbouring scalars are studied by a combination of numerical and analytical methods from the dynamical system theory. Many dynamical effects are reviewed with emphasis on the emergence of chaotic motion of the vortex phase trajectories and the scalars in their immediate vicinity.

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“…Deformation flows always appear near topography boundaries, coherent vortices, jets, large-scale gyres or other non-uniform flows. More generally, an arbitrary external perturbation can be expanded into a Taylor series up to the second order terms, which gives the following flow form [54,55,57,58,61,84,89,[91][92][93][94][95][96][97][98][99]…”

Section: External Deformation Flowmentioning

confidence: 99%

“…This configuration allows us to study the advection of upper-layer fluid particles perturbed by the periodic motion of the lower-layer vortices. This model thus may help shed light into the problem of identifying the signs of the subsurface vortices by their imprints on the ocean surface advection [6,94,[157][158][159][160][161][162][163][164].…”

Section: Fluid Particle Advection In Singular Vortex Systems In Layermentioning

confidence: 99%

Vortex Interactions Subjected to Deformation Flows: A Review

Koshel¹,

Ryzhov²,

Carton³

2018

Preprint

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Deformation flows are flows incorporating shear, strain and rotational components. These flows are ubiquitous in the geophysical flows, such as the ocean and atmosphere. They appear near almost any salience, such as isolated coherent structures (vortices and jets), various fixed obstacles (submerged obstacles, continental boundaries). Fluid structures subject to such deformation flows may exhibit drastic changes in motion. In this review paper, we focus on the motion of a small number of coherent vortices embedded in deformation flows. Problems involving isolated one and two vortices are addressed. When considering a single-vortex problem, the main focus is on the evolution of the vortex boundary and its influence on the passive scalar motion. Two vortex problems are addressed with the use of point vortex models, and the resulting stirring patterns of neighbouring scalars are studied by a combination of numerical and analytical methods from the dynamical system theory. Many dynamical effects are reviewed with emphasis on the emergence of chaotic motion of the vortex phase trajectories and the scalars in their immediate vicinity.

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Observations of Tilting Meddies

Cited by 9 publications

References 0 publications

Simulations of Acoustic Imprints of Meddies in the Iberian Basin: Toward Acoustic Detection of Meddies

Simulations of Acoustic Imprints of Meddies in the Iberian Basin: Toward Acoustic Detection of Meddies

Vortex Interactions Subjected to Deformation Flows: A Review

Vortex Interactions Subjected to Deformation Flows: A Review

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